Slippery2000

Alright y'all, please pardon me for saying y'all, it's just that this Tampa Bay, FL heat is really bogging me down literally & figuratively.

Story time! - I acquired the car late September last year... everything was cool. Had an issue where it wouldn't start & it took a few trips/months to diagnose but it was a simple loose connection from the previous folks who replaced the starter! Anyway, I'm starting to wonder what else is lurking as I've only had issues. This was a used purchase from a Nissan dealership. 110k miles or so. 140k now. Don't ask (that's goes for why would I buy one with 110k & how does it have 30k more miles already). LOL.

Anyway, between the starting issue, I've had misfires occur 4 times (today is the 4th). Had a valve adjustment done at a reputable performance shop, yet it only took 4 hours... same day. So they didn't wait for it to cool the ideal amount (overnight). It ran better, maybe, but I didn't really have anything "better" to compare it to since apparently it's never ran top notch since I got it, but again, I had nothing to compare it with. No other S2000s.

That took care of the second round of misfires (first round was plugs). Third set of misfires occured a few weeks later. Plugs were shot, coil packs were replaced, & my normal (non-performance) shop discovered the valves were way off from the last adjustment. They kept it overnight & it was completely fine for 1-2 months except in the 2 month (this June) it started to seem like it was taking more throttle to get around & the car sounds like it's working harder to do anything, just a lot louder. & on top of that, it's got a funky thing going on where at idle at stoplights, you can here the metal contraction sounds echoing off the traffic beside you - the sound cars make when you turn them off & the heat dissipation occurs... it makes that sound pretty much ALL the time. I've never experienced that before in any vehicle.

& now today, alas, misfires out of the blue. Was running "normal" earlier & I started it up & CEL is steady, idle is now rough beyond belief. Codes 0300, 0303, 0304, 1399. The usual misfire codes!

So, gonna have the normal place check it out tomorrow, but wanted to see if anyone had any insight as to what the hell is going on with my vehicle. I adore the S2000 as we all do, & I would like it to run properly. I'm not looking to mod the shit out of it or anything, I want it to look good & be reliable! Is that really too much to ask? The car is completely stock & I intend to keep it that way as it's plenty fast for me in all the wonderful traffic we have around here.

If this car keeps acting up I'll be going through LHT only (they replaced my top & fixed some screwy wiring from prev owners). I just wish they had more availability since they're like 20 minutes away. Y'all need to stop ordering superchargers for like a week lol

noodels

Maybe need to put 4 new coils in.

Slippery2000

Sorry for the ninja edit 3 minutes ago, all 4 packs were replaced when the second adjustment was done!

Chuck S

Did I miss what engine you have? May or not be important but probably useful. It does make a difference in the valve lash settings and (I think) the coil packs. OEM plugs I assume?

-- Chuck

Slippery2000

OEM plugs, 7772 or what have you. That may be the other set but it has the plugs that the majority of us go with. F20C1. Supposedly has AP2 retainers (per what the dealer said) if that would even be possible or a typical upgrade for an AP1. Seems like an odd thing to make up so

Anyway, I just started it again & now it's making a loud ass somewhat high tone humming sound from the bay? Quick search says may be relative to the idle issue & the intake is losing it's shit trying to compensate. It's annoyingly loud. Never heard it before.

V3rtigo

I believe the valves are to be adjusted when the engine is still hot because you want it set for where the engine will be most of the time. I'll check the Honda shop manual when I'm home to be sure.

If you burnt the valves due to the valves being tight, adjusting them won't fix the problem. You will need to pull the head to fix them. But the symptoms you are describing could be a bunch of things. Has the timing chain been replaced? That could be the source of your power and noise issues. The chain tensioner could also be part of the issue.

Slippery2000

Not sure if the timing chain has ever been replaced since there were of course no service records provided. I've watched TCT sound videos but there's nothing like that going on.

However, I've now learned the humming sound is something I just now induced by having the intake box open on start up. Apparently it won't go away if you do it once - even if you start up with the cover secured again, unless maybe you reset the ECU.

Anyway, I took it for a spin with the cover off (stock cone intake) to see what everyone meant by "it will be louder." WELL HOT DAMN, it's hella loud hahaha! Makes it sound like a V8 in my naive ears. Anyway, I took it around some empty curvy roads for about 5 minutes & it seemed to drive better than when I got it last year. Not sure if it's a combo of it being 10 degrees cooler outside vs earlier today + possibly better airflow since the cover was off? Too bad the air in cover-off mode would probably lead to guaranteed heatsoak during my normal driving hours, & my drives are about 30 miles each way.

That sound is incredible though. Was a much needed spirit boost lol. I do want to invest in a CAI someday to help with this FL heat & get some sound as a bonus. Beyond that & maybe an exhaust. That's as far as I'd go since a supercharger is out of the question for years. So only like .0008 modded lol.

I'm still going to leave the CEL codes intact even though it seemed to run like a champ just now so it'll be checked into tomorrow & I'll bring up the major maintenance items (timing chain, etc.) to see if that will get everything proper again.

Edit------------
Also going to look into the CAT possibly having to do with rattle & or power issues. Can't seem to tap it hard enough to check if that's an obvious issue since I don't have jack stands.

windhund116

Just the opposite. Clearances for most cars (including the S2000), is when engine is cold. Overnight cold.

https://robrobinette.com/S2000ValveAdjust.htm

Chuck S

Honda wants the engine below 100°F. Just moving the car indoors will heat the engine above that temperature.

-- Chuck